Applied Physiology and Nutrition Research Group, School of Physical Education and Sport; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Av. Dr. Arnaldo, 455-Cerqueira César, São Paulo, SP, CEP 01246903, Brazil.
Institute of Orthopedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil.
Sports Med. 2022 Sep;52(9):2209-2220. doi: 10.1007/s40279-022-01685-0. Epub 2022 May 10.
The aim was to quantify the proportion of the literature on caffeine supplementation that reports habitual caffeine consumption, and determine the influence of habitual consumption on the acute exercise response to caffeine supplementation, using a systematic review and meta-analytic approach.
Three databases were searched, and articles screened according to inclusion/exclusion criteria. Three-level meta-analyses and meta-regression models were used to investigate the influence of habitual caffeine consumption on caffeine's overall ergogenic effect and within different exercise types (endurance, power, strength), in men and women, and in trained and untrained individuals. Sub-analyses were performed according to the following: acute relative dose (< 3, 3-6, > 6 mg/kg body mass [BM]); whether the acute caffeine dose provided was lower or higher than the mean daily caffeine dose; and the caffeine withdrawal period prior to the intervention (< 24, 24-48, > 48 h).
Sixty caffeine studies included sufficient information on habitual consumption to be included in the meta-analysis. A positive overall effect of caffeine was shown in comparison to placebo (standard mean difference [SMD] = 0.25, 95% confidence interval [CI] 0.20-0.30; p < 0.001) with no influence of relative habitual caffeine consumption (p = 0.59). Subgroup analyses showed a significant ergogenic effect when the caffeine dose was < 3 mg/kg BM (SMD = 0.26, 95% CI 0.12-0.40; p = 0.003) and 3-6 mg/kg BM (SMD = 0.26, 95% CI 0.21-0.32; p < 0.0001), but not > 6 mg/kg BM (SMD = 0.11, 95% CI - 0.07 to 0.30; p = 0.23); when the dose was both higher (SMD = 0.26, 95% CI 0.20-0.31; p < 0.001) and lower (SMD = 0.21, 95% CI 0.06-0.36; p = 0.006) than the habitual caffeine dose; and when withdrawal was < 24 h, 24-48 h, and > 48 h. Caffeine was effective for endurance, power, and strength exercise, with no influence (all p ≥ 0.23) of relative habitual caffeine consumption within exercise types. Habitual caffeine consumption did not modify the ergogenic effect of caffeine in male, female, trained or untrained individuals.
Habitual caffeine consumption does not appear to influence the acute ergogenic effect of caffeine.
本研究旨在通过系统评价和荟萃分析的方法，量化补充咖啡因文献中报告习惯性咖啡因摄入的比例，并确定习惯性摄入对咖啡因补充后急性运动反应的影响。
检索了三个数据库，并根据纳入/排除标准筛选文章。使用三级荟萃分析和荟萃回归模型，研究习惯性咖啡因摄入对咖啡因整体促进作用的影响，并在男性和女性、训练和未训练个体中，以及不同运动类型（耐力、力量、强度）中，研究咖啡因的影响。根据以下情况进行亚组分析：急性相对剂量（<3、3-6、>6mg/kg 体重[BM]）；急性咖啡因剂量是否低于或高于平均每日咖啡因剂量；以及干预前的咖啡因戒断期（<24、24-48、>48h）。
纳入的 60 项咖啡因研究提供了足够的习惯性消费信息，可用于荟萃分析。与安慰剂相比，咖啡因表现出积极的总体效果（标准均数差[SMD] = 0.25，95%置信区间[CI] 0.20-0.30；p<0.001），而习惯性咖啡因摄入的相对量无影响（p=0.59）。亚组分析显示，当咖啡因剂量<3mg/kg BM（SMD=0.26，95%CI 0.12-0.40；p=0.003）和 3-6mg/kg BM（SMD=0.26，95%CI 0.21-0.32；p<0.0001）时，咖啡因具有显著的促进作用，但当剂量>6mg/kg BM 时（SMD=0.11，95%CI -0.07 至 0.30；p=0.23）时则没有；当剂量高于（SMD=0.26，95%CI 0.20-0.31；p<0.001）和低于（SMD=0.21，95%CI 0.06-0.36；p=0.006）习惯性咖啡因剂量时；当戒断时间<24、24-48 和>48h 时，咖啡因对耐力、力量和力量运动均有效，且在运动类型内，习惯性咖啡因摄入的相对量无影响（均 p≥0.23）。习惯性咖啡因摄入并没有改变咖啡因对男性、女性、训练和未训练个体的促进作用。
习惯性咖啡因摄入似乎不会影响咖啡因的急性促进作用。
